The biomass in the upper trophic levels is generally ______ as compared to the lower trophic levels.

The correct answer is Very low.

Key Points

• The biomass in higher trophic levels (e.g., carnivores) is less than in lower trophic levels (e.g., plants).
• This phenomenon is due to energy loss at each trophic level as energy is transferred.
• Only about 10% of the energy is transferred from one trophic level to the next; the rest is lost primarily through metabolic processes.
• The pyramid of biomass typically shows a decreasing trend from primary producers to apex predators.
• This decrease in biomass is a direct result of the second law of thermodynamics which states that energy transformations are not 100% efficient.

Additional Information

• Trophic Levels:
  • Each step in a food chain or food web is called a trophic level.
  • Primary producers (e.g., plants) occupy the first trophic level.
  • Herbivores, which eat plants, occupy the second trophic level.
  • Carnivores that eat herbivores occupy the third trophic level, and so on.
• Energy Transfer Efficiency:
  • Energy transfer between trophic levels is typically around 10%, known as the 10% law.
  • 90% of the energy is lost to the environment as heat, movement, or undigested food.
• Pyramid of Biomass:
  • It is a graphical representation showing the relative biomass at each trophic level.
  • The pyramid typically narrows at higher trophic levels.
  • The biomass of primary producers is the highest, followed by primary consumers, secondary consumers, and so forth.
• Second Law of Thermodynamics:
  • This law states that energy transformations are not 100% efficient.
  • In an ecosystem, this inefficiency is observed as energy is lost as heat at each trophic level transfer.